
mxallowd
(c) 2007-2008 Michael Stapelberg
http://michael.stapelberg.de/mxallowd


mxallowd is a daemon which uses libnetfilter_queue to allow
(or deny) connections to a mailserver (or similar
application) if the remote host hasn't connected to a
fake daemon before.

This is an improved version of the so-called nolisting 
(see http://www.nolisting.org/). The assumption is that spammers
are not using RFC 2821-compatible SMTP-clients and are
sending fire-and-forget spam (directly to the first or second
MX-entry without retrying on error). This direct access is
blocked with mxallowd, you'll only get a connection if you
retry.


This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; in version 2
of the License.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301 USA
Or, point your browser to http://www.gnu.org/copyleft/gpl.html
